Is the phenology of all restinga species the same? A taxonomically-focused study of Sapindaceae in a highly threatened coastal environment

Abstract

Restingas are highly threatened coastal ecosystems located in the Atlantic Forest domain that host a great diversity of plants, including many endemics. Though expanding transportation infrastructure and real estate development have rapidly destroyed extensive portions of natural restinga landscapes along the entire Brazilian coast, comparative phenological studies and conservation programs focused on protecting restinga species are extremely rare. As a result, we currently have a poor understanding of phenological patterns of most plant groups in this habitat. Therefore, aiming to answer the question “Is the phenology of all restinga species the same?”, we designed a taxonomically-focused comparative study of Sapindaceae in the Restinga da Marambaia, Rio de Janeiro, Brazil. The vegetative and reproductive phenology of four species with a diversity of life forms was analyzed over 24 months: Allophylus puberulus (shrub), Matayba intermedia (tree), Cupania emarginata (tree) and Paullinia coriacea (liana). We found that leaf flush and leaf fall occurred throughout the year for all species. However, they exhibited very different reproductive phenological patterns. Allophylus puberulus showed a nearly continuous, but irregular expression of reproductive phenophases throughout the year, while the other three species have distinct non-overlapping phenological maxima. We also investigated the relationship between phenology and environmental parameters. Most correlations were found with temperature and day length rather than precipitation. However, there was no strong, consistent pattern of phenological events correlating with abiotic stimuli. A detailed discussion of how these patterns compare with other phenological studies of Sapindaceae is included. We conclude that taxonomically focused phenological analyses provide a powerful perspective, and future studies coupling phenology with phylogenetics will yield further insight.